M13.161 Monoarthritis, not elsewhere classified, right knee

Billable ICD-10-CM code, FY2026.

Applies from M13 Other arthritis

Excludes1 (never code together)

• arthrosis (M15-M19)
• osteoarthritis (M15-M19)

MS-DRG index

Defines the logic of DRG(s) 553-554 in MDC 08.

Approximate ICD-9-CM (GEMs)

• 716.66 Unspecified monoarthritis, lower leg (approximate)

Nearby codes

• M13.15 Monoarthritis, not elsewhere classified, hip
• M13.151 Monoarthritis, not elsewhere classified, right hip
• M13.152 Monoarthritis, not elsewhere classified, left hip
• M13.159 Monoarthritis, not elsewhere classified, unspecified hip
• M13.16 Monoarthritis, not elsewhere classified, knee
• M13.161 Monoarthritis, not elsewhere classified, right knee (this code)
• M13.162 Monoarthritis, not elsewhere classified, left knee
• M13.169 Monoarthritis, not elsewhere classified, unspecified knee
• M13.17 Monoarthritis, not elsewhere classified, ankle and foot
• M13.171 Monoarthritis, not elsewhere classified, right ankle and foot
• M13.172 Monoarthritis, not elsewhere classified, left ankle and foot